Burglar-alarm



(No Model.)

A. JACOBI.

BURGLAR ALARM. l10.320.660'. Patented June 23,1885.

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@a J( L @Gf i M UNITED STATES PATENT OFFICE..

ALEXANDER JACCBI, OF ST. CLAIR, MICHIGAN.

BU RGLAR-ALARM.

SPECIFICATION forming part of Letters Patent No.320,660, dated June 23, 1885.

Application sind April 15, isst. (No mofui.)

To @ZZ whom it may concern.-

Be it known that I, ALEXANDER JAcoEr,

` of St. Clair, in the county of St. Clair and State of Michigan, have invented new and useful Improvements in Burglar-Alarms; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, which form a part of this specification.

This invention relates to a new and useful improvement in burglar-alarms of that kind where the ringing of the alarm-bell is pro` duced by mechanical means.

The object of my invention is to improve the device described in a patent granted to me March 24, 1885, No. 314,450; and the i1nprovement consists in the arrangement of certain devices, hereinafter described, forconnecting doors or windows with the alarm-cord.

Figure 1 is a perspective view of a door to which my device for operating the alarm is applied. Fig. 2 shows a part of Fig. l on a larger scale. Fig. 3 is a detached perspective view of the weight-supporting staple. Fig. 4 is a horizontal cross-section of a door opening toward the outside, and to which a modified form of my device is applied. Fig. 5 shows my device as applied to a window.

In the accompanying drawings, which form a part of this specification, A is the burglaralarm operated by clock-work in the usual manner, and provided with the alarm-bell B i and hammer C. D is a vertical sliding detent, which, when engaging into the eye E on the hammer-arm, locks the hammer in position, and which, when lifted up by a pull on the alarm-cord F, liberates the hammer and allows it to 'ring the bell.

The parts just described are subst-antially the same shown in my abovementioned patent.

To protect a door with a burglar-alarm of this kind, I have arranged the following contrivance: Gis a weight attached to a branch cord, H, which runs up vertically, then passes over a pulley, I, or through a staple, and, after running alittle distance in a horizontal direction, connects with the main alarm-cord F. K is a staple driven into the door-casing, so as to form a support on which the weight G may stand. I preferably cover the staple K with a little tin plate, L, suitably secured thereto, as shown in Fig. 8, so as to form a convenient platform for the weight. M is a little sliding rod, secured to the door in such position that it may be projected behind the weight. Vith the parts thus arranged it will be seen that on opening the door the rod M will push the weight G off the platform. Its gravity in falling will-then pull the alarmcord, lifting the detent D and setting the alarm to ring.

It will be seen that by an arrangement of this kind the alarm-cords F H can lbe arranged with a considerable slack, and no failure or false alarm can occur,owiug to the contraction or expansion of the alarmcords, pro viding the weight G is put sufficiently high above the floor to give it a considerable fall to take up the slack of the cords. As the operation of the weight is almost instantaneous, as soon as the door is opened the least bit, no amount of dexterity or knowledge on the part of the intruder can defeat its object.

To disconnect the door from the alarmcord the weight G is taken off its platform and hung on anail or hook, N, conveniently secured nea-r by, and the arm Mis retracted out of the way.

For an outside door I arrange the weight and platform on the inside of the door-jamb, as shown in Fig. 4, and provide the arm M with a little return-bend, O, which, when the door is opened, will pull the weight off the platform.

The device, if desired, may be equally well applied to windows, in which case the parts are suitably arranged to operate by the rais ing of thelower sash, as shown in Fig. 5, in which case the pin m is attached to the window-sash, and is bent as shown. When the window is raised,`this inclined portion, acting as a wedge, forces the weight off its platform by reason of its engagement with the piu m, with which the weight is provided.

It will be seen that my coutrivance permit-s of connecting all the doors and windows of a dwelling to one alarm.

That I claim as my invention is-e l. In a burglar-alarm, the combination of a weight-supporting platform arranged in proximity to a door or window, a weight attachedlonthe operatingcord and.snpp'oted sliding rod M, and alarm-Cords H I, al1 comby said platform, and a rod arranged in the bined and operating as described;

path of the weight, whereby the opening,` of Detroit', Michigan, Apri13, 1885.

the door or Window moves the Weight from its 5 platform, substantially as and for the purpose A `l ALEXANDER JACOBI' specied. Y In presence' ofthe combination of the weight G, staple K, E. J. SCULLY.

2. In aburglaralarm operatingas described, H. S. SPRAGUE, 

